This question tests understanding of trigonometric ratios in right triangles and their relationships. Following the method in Example 4 from the context, we first determine sin A and cos A from the given tan A value. Then using the complementary angle relationship (A + C = 90° in a right triangle), we find sin C and cos C. The expressions simplify to standard compound angle formulas: sin(A+C) and cos(A-C), which evaluate to sin 90° = 1 and cos 90° = 0 respectively.